This invention relates to recording and/or playback apparatus and, more particularly, to indexing apparatus for indicating the amount of information recorded on or transcribed from the record medium used in such recording and/or playback apparatus.
In the use of recording/playback devices for dictation purposes, an index, such as a scale, often is used to indicate the amount of information that has been recorded on the record medium. In many instances, an operator desires to indicate the location of various instructions along the record medium, such as by selectively marking the scale. Typical of such instructions are inserts, deletions, the end of a selected piece of dictation, and the like. Marking of the scale to indicate instructions generally is preferred over the physical marking of the record medium, as by an ink or crayon mark, by a perforation, etc.
The prior art has developed improved indicating mechanisms which scribe marks on an indicating slip usually incorporated into the dictation apparatus. Typically, the slip is incorporated into the index scale, graduated in minutes and marked by, for example, a pencil or the like, by the operator. In many dictation devices, automatic marking devices also have been incorporated into the apparatus. Accordingly, the operator merely need actuate suitable controls on the apparatus to effect a corresponding mark on the index scale.
Although the marked index scale provides a generally adequate indication to a transcriptionist of the relative location of instructions on the record medium, there is the possibility that the marked index scale will be lost or otherwise separated from the record medium. This means that the transcriptionist cannot be apprised of such instructions at the outset of a transcribing operation, thereby contributing to possible confusion, erroneous transcription of dictated information or inordinate delay in completing the transcription.
In an attempt to overcome this problem attending separate, marked index scales, it has been proposed to record predetermined instruction signals on the record medium, these predetermined signals performing substantially the same function as the markings on the index scale. For example, the predetermined instruction signals can be recorded as tone signals which are not audibly sensed during playback. In preparation of a transcribing operation, the record medium is rapidly scanned to detect the presence of these tone signals and to mark an index strip which is scanned in synchronism with the scanning of the record medium when each such signal is detected. One example of such an instruction indicator apparatus is described in U.S. Pat. No. 3,040,135. Various types of marking mechanisms and index strips can be used, and one system proposes a thermosensitive index scale.
Although the technique of recording instruction signals substantially avoids the problem of lost index slips, it is necessary to provide a fresh index slip for each change in the record medium. For example, if the record medium is a magnetic belt, the scanning of that belt will mark one index slip, and the next belt which is transcribed requires the preparation of another index slip. Similarly, if the record medium is magnetic tape, such as a tape cassette, each new cassette requires the preparation of an associated index slip. Hence, index slips must be kept in ready supply.
Another problem attending the marking of index slips in response to recorded instruction signals is that of insuring that the marks on the index scale are in correspondence with the instructions on the record medium. For example, if it is assumed that during recording or transcription the index scale is scanned by an indicator in a first, for example, left-to-right, direction, then during a reverse or backspace operation or in preparation for transcription, wherein it is necessary to position the playback head at the beginning portion of the record medium, the indicator scans the scale in a second opposite, or right-to-left, direction. The problem arises in first positioning the indicator at some position along the scale before the backspace operation commences if less than all of the record medium has been used for recording. That is, if the indicator is not positioned exactly at the location corresponding to the amount of medium which had been used, then the marks on the scale will not correspond to the recorded instruction locations, and at the conclusion of the backspace operation the indicator may not be located at the start, or zero, position.